drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c

// SPDX-License-Identifier: GPL-2.0-only
/*******************************************************************************
  Copyright (C) 2013  Vayavya Labs Pvt Ltd

  This implements all the API for managing HW timestamp & PTP.


  Author: Rayagond Kokatanur <rayagond@vayavyalabs.com>
  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
*******************************************************************************/

#include <linux/io.h>
#include <linux/delay.h>
#include "common.h"
#include "stmmac_ptp.h"

static void config_hw_tstamping(void __iomem *ioaddr, u32 data)
{
	writel(data, ioaddr + PTP_TCR);
}

static void config_sub_second_increment(void __iomem *ioaddr,
		u32 ptp_clock, int gmac4, u32 *ssinc)
{
	u32 value = readl(ioaddr + PTP_TCR);
	unsigned long data;
	u32 reg_value;

	/* For GMAC3.x, 4.x versions, in "fine adjustement mode" set sub-second
	 * increment to twice the number of nanoseconds of a clock cycle.
	 * The calculation of the default_addend value by the caller will set it
	 * to mid-range = 2^31 when the remainder of this division is zero,
	 * which will make the accumulator overflow once every 2 ptp_clock
	 * cycles, adding twice the number of nanoseconds of a clock cycle :
	 * 2000000000ULL / ptp_clock.
	 */
	if (value & PTP_TCR_TSCFUPDT)
		data = (2000000000ULL / ptp_clock);
	else
		data = (1000000000ULL / ptp_clock);

	/* 0.465ns accuracy */
	if (!(value & PTP_TCR_TSCTRLSSR))
		data = (data * 1000) / 465;

	data &= PTP_SSIR_SSINC_MASK;

	reg_value = data;
	if (gmac4)
		reg_value <<= GMAC4_PTP_SSIR_SSINC_SHIFT;

	writel(reg_value, ioaddr + PTP_SSIR);

	if (ssinc)
		*ssinc = data;
}

static int init_systime(void __iomem *ioaddr, u32 sec, u32 nsec)
{
	int limit;
	u32 value;

	writel(sec, ioaddr + PTP_STSUR);
	writel(nsec, ioaddr + PTP_STNSUR);
	/* issue command to initialize the system time value */
	value = readl(ioaddr + PTP_TCR);
	value |= PTP_TCR_TSINIT;
	writel(value, ioaddr + PTP_TCR);

	/* wait for present system time initialize to complete */
	limit = 10;
	while (limit--) {
		if (!(readl(ioaddr + PTP_TCR) & PTP_TCR_TSINIT))
			break;
		mdelay(10);
	}
	if (limit < 0)
		return -EBUSY;

	return 0;
}

static int config_addend(void __iomem *ioaddr, u32 addend)
{
	u32 value;
	int limit;

	writel(addend, ioaddr + PTP_TAR);
	/* issue command to update the addend value */
	value = readl(ioaddr + PTP_TCR);
	value |= PTP_TCR_TSADDREG;
	writel(value, ioaddr + PTP_TCR);

	/* wait for present addend update to complete */
	limit = 10;
	while (limit--) {
		if (!(readl(ioaddr + PTP_TCR) & PTP_TCR_TSADDREG))
			break;
		mdelay(10);
	}
	if (limit < 0)
		return -EBUSY;

	return 0;
}

static int adjust_systime(void __iomem *ioaddr, u32 sec, u32 nsec,
		int add_sub, int gmac4)
{
	u32 value;
	int limit;

	if (add_sub) {
		/* If the new sec value needs to be subtracted with
		 * the system time, then MAC_STSUR reg should be
		 * programmed with (2^32 – <new_sec_value>)
		 */
		if (gmac4)
			sec = -sec;

		value = readl(ioaddr + PTP_TCR);
		if (value & PTP_TCR_TSCTRLSSR)
			nsec = (PTP_DIGITAL_ROLLOVER_MODE - nsec);
		else
			nsec = (PTP_BINARY_ROLLOVER_MODE - nsec);
	}

	writel(sec, ioaddr + PTP_STSUR);
	value = (add_sub << PTP_STNSUR_ADDSUB_SHIFT) | nsec;
	writel(value, ioaddr + PTP_STNSUR);

	/* issue command to initialize the system time value */
	value = readl(ioaddr + PTP_TCR);
	value |= PTP_TCR_TSUPDT;
	writel(value, ioaddr + PTP_TCR);

	/* wait for present system time adjust/update to complete */
	limit = 10;
	while (limit--) {
		if (!(readl(ioaddr + PTP_TCR) & PTP_TCR_TSUPDT))
			break;
		mdelay(10);
	}
	if (limit < 0)
		return -EBUSY;

	return 0;
}

static void get_systime(void __iomem *ioaddr, u64 *systime)
{
	u64 ns, sec0, sec1;

	/* Get the TSS value */
	sec1 = readl_relaxed(ioaddr + PTP_STSR);
	do {
		sec0 = sec1;
		/* Get the TSSS value */
		ns = readl_relaxed(ioaddr + PTP_STNSR);
		/* Get the TSS value */
		sec1 = readl_relaxed(ioaddr + PTP_STSR);
	} while (sec0 != sec1);

	if (systime)
		*systime = ns + (sec1 * 1000000000ULL);
}

const struct stmmac_hwtimestamp stmmac_ptp = {
	.config_hw_tstamping = config_hw_tstamping,
	.init_systime = init_systime,
	.config_sub_second_increment = config_sub_second_increment,
	.config_addend = config_addend,
	.adjust_systime = adjust_systime,
	.get_systime = get_systime,
};